Optical switch

• US 6,809,853 B2
• Filed: 04/04/2002
• Issued: 10/26/2004
• Est. Priority Date: 04/04/2002
• Status: Expired due to Fees

• Current Assignee: Comptic Incorporated
• Original Assignee: Comptic Incorporated
• Inventors: Culver, William H.
• Primary Examiner(s): Sugarman, Scott J.
• Assistant Examiner(s): Hanig, Richard
• Application Number:
  US10/115,249
• Publication Number:
  US 20030190115A1
• Time in Patent Office: 936 Days
• Field of Search: 359/291, 359/245, 359/260, 359/261, 359/263, 359/315, 359/317, 359/318, 359/320, 359/223, 385/18
• US Class Current: 359/291
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29358 Multiple beam interferometer external to a light guide, e.g. Fabry-Pérot, etalon, VIPA plate, OTDL plate, continuous interferometer, parallel plate resonator G02B6/29347, G02B6/29349, G02B6/2935, G02B6/29361 take precedence; resonator evanescently coupled to light guide G02B6/29335
• CPC Class Codes: G02B 6/29373 utilising a bulk dispersive element, e.g. prism
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/3516 the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02F 1/055 the active material being a ceramic G02F1/035 takes precedence
• CPC Class Codes: G02F 1/21 by interference
• CPC Class Codes: G02F 2203/24 beam steering

Abstract

An optical switch for an optical network, which can switch a light beam from and input fiber to an output fiber quickly and without expensive intermediate conversions to electrical form. The optical switch changes the relative phase of the individual portions of a cross section of a wave front of a beam using wave front interference and can be used in packet switching with switching speeds of about 10 nanoseconds. These optical switches use a phase spatial light modulators (PSLM) that include an array of phase shifting elements preferably of Gires-Tournois interferometers. Each of the phase shifting elements has either a stationary reflective surface with a movable reflective surface or an electro-refractive medium sandwiched between two stationary surfaces. In the first embodiment, the stationary reflective surface with a movable reflective surface is kept a known distance apart by applied potential. In the second embodiment, an applied potential across the electro-refractive medium changes the optical wave path length of the phase shifting element. In a third embodiment, a prism or other spectral dispersing element is used to spectrally separate different wavelengths of a beam carrying a wavelength division multiplexed signal in a Litrow configuration. A spatial light modular is then used to controllably steer the separated wavelengths to a desired directions.

Claims

1. An apparatus, comprising:

an optical switch controllably steering a direction of a light beam by interferometrically changing a phase and having an array of interferometers with each of the interferometers changing the phase of a portion of the beam.

2. An apparatus as recited in claim 1, wherein the beam is divided into pixels and each pixel comprises a spring held mirror having a position adjusted by depositing a known charge upon mirror electrodes and a backplane mirror spaced a known distances from the spring held mirror.

3. An apparatus as recited in claim 1, wherein the phase of the wave front is changed in segments by a plurality of phase shifting elements.

4. An apparatus as recited in claim 3, wherein each of the phase shifting elements have two reflective surfaces which produce wave front interference from the beam.

5. An apparatus as recited in claim 3, wherein each phase shift element comprises an assembly having a first mirror and second mirror substantially parallel to the first mirror, said mirrors movably mounted with respect to one another.

6. An apparatus as recited in claim 5, wherein a known distance of the mirrors of the phase shifting element is adjustable by depositing charge upon mirror electrodes.

7. An apparatus, as recited in claim 1, wherein said switch comprises an interferometric phase spatial light modulator changing the direction of the beam.

8. An apparatus as recited in claim 5, wherein the first mirror of the assembly is a spring held mirror having a position adjusted by a voltage.

9. An apparatus as recited in claim 5, wherein the first mirror of each phase shifting element has a reflectivity of about 90%.

10. An apparatus as recited in claim 5, wherein the second mirror of each phase shifting element has a reflectivity of about 99.9%.

11. An apparatus as recited in claim 5, wherein each phase shifting element is an interferometer.

12. An apparatus as recited in claim 5, wherein each phase shifting element is a Gires-Tournois interferometer.

13. An apparatus as recited in claim 1, wherein the beam is divided into pixels and each pixel comprises:

a transparent substrate;

a spring held mirror on the substrate having a position adjusted by depositing a known charge upon mirror electrodes; and

a backplane mirror covering the substrate and between the substrate and the spring held mirror;

wherein the mirrors of each pixel are spaced known distances.

14. An apparatus as recited in claim 1, wherein

the beam steering is produced by changing optical wave path length in a plurality of phase shifting elements.

15. An apparatus as recited in claim 3, wherein wave front interference is produced by substantially reflections off the phase shifting elements of the incident beam of light.

16. An apparatus as recited in claim 1, wherein the beam steering is produced by wave front interference in a plurality of optical resonance cavities.

26. An apparatus as recited in claim 1, wherein the optical switching speed of the beam from one output port to another output port is less than or equal to 10 nanoseconds.

27. An apparatus as recited in claim 1, wherein the optical switching speed of the beam from one output port to another output port is less than or equal to 100 nanoseconds.

17. An optical switch, comprising:

an array of phase shifting elements, each of said phase shifting elements comprising an interferometer shifting a portion of a wave front by interferometrically changing the direction of an optical beam.

18. An optical switch as recited in claim 17, wherein the phase shifting elements shift the beam from an input port to one of plural output ports.

19. An optical switch as recited in claim 17, wherein no phase shifting element is moved more that ¼

wavelength distance relative to adjoining phase shifting elements.

20. An optical switch as recited in claim 17, in which the movement of the phase shifting element is substantially eliminated.

21. An optical switch as recited in claim 17, wherein each of said phase shifting elements changes a length of an optical path of the beam.

22. A method, comprising:

directing a plurality of pixels of a light beam at respective phase shifting elements comprising interferometers; and

shifting the phase of each of the pixels of the light beam by a predetermined amount to controllably steer the light beam to a desired direction.

23. A method as recited in claim 22, wherein the shifting is caused by applying a potential to produce a known separation between reflective surfaces.

24. A method as recited in claim 22, wherein the shifting is caused by changing an optical length of the beam, reflective surfaces being substantially stationary with respect to one another.

25. An optical switch with a spectral dispersing element comprising;

a plurality of spatial light modulators comprising interferometers;

a lens;

an input light beam having as least two wavelength channels passes through the lens;

a spectral dispersing element configured between one or more of the spatial light modulators and the lens, the light beam, which enters the spectral dispersing element, produces chromatic dispersion of the at least two wavelength channels, the at least wavelength channels of the light beam, which are incident on the one or more spatial light modulators, are controllably steered back through the spectral dispersing element, after exiting the spectral dispersing element the at least two dispersion channels are focused by the lens on an array of desired positions.

28. An apparatus, comprising:

an array of interferometric phase spatial light modulators which controllably produce a wave front desired phase distribution from a beam of light.

29. An apparatus as recited in claim 28 in which the array of interferometric phase spatial light modulators use Gires-Tournois interferometers.